diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 92246117d2b0..465952a8e465 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2896,6 +2896,15 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, u64 umin_val, umax_val; u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32; + if (insn_bitness == 32) { + /* Relevant for 32-bit RSH: Information can propagate towards + * LSB, so it isn't sufficient to only truncate the output to + * 32 bits. + */ + coerce_reg_to_size(dst_reg, 4); + coerce_reg_to_size(&src_reg, 4); + } + smin_val = src_reg.smin_value; smax_val = src_reg.smax_value; umin_val = src_reg.umin_value; @@ -3131,7 +3140,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, if (BPF_CLASS(insn->code) != BPF_ALU64) { /* 32-bit ALU ops are (32,32)->32 */ coerce_reg_to_size(dst_reg, 4); - coerce_reg_to_size(&src_reg, 4); } __reg_deduce_bounds(dst_reg); @@ -3163,7 +3171,7 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, * an arbitrary scalar. Disallow all math except * pointer subtraction */ - if (opcode == BPF_SUB){ + if (opcode == BPF_SUB && env->allow_ptr_leaks) { mark_reg_unknown(env, regs, insn->dst_reg); return 0; } |